Posted on 05/22/2006 4:52:42 PM PDT by blam
Risk of asteroid smashing into Earth reduced
12:50 22 May 2006
NewScientist.com news service
Kelly Young
The asteroid's path through the solar system will bring it to close to Earth in 2029 (Image: JPL/NASA)
The danger to Earth from an asteroid called Apophis, which once looked relatively likely to hit the Earth, appears to be waning.
The odds of an Earth impact by Apophis in 2036 have now been reduced from 1 in 5500 to 1 in 24,000, following new radar measurements taken by the Arecibo Observatory in Puerto Rico.
On 6 May 2006, with the asteroid 42 million kilometres away, astronomers with NASA's Jet Propulsion Laboratory measured the speed of the asteroid with radar. They found its speed was 6 millimetres per second different than what they had expected.
"It's just a small correction in the orbit that propagates forward in time enough to reduce the probability of impact," says Jon Giorgini, senior analyst with the Solar System Dynamics Group at JPL in Pasadena, California, US.
Before this observation, it was thought that in 2029 Apophis would approach our planet to within about 5.86 Earth radii. With these new measurements, the estimated distance has been pushed back to 5.93 Earth radii.
Through the keyhole This seemingly small difference is crucial since if the asteroid's path carries it through a certain "keyhole" – in this case, a specific region of space near Earth just 600 metres across – Apophis's orbit could be perturbed enough to put it on a collision course with Earth in 2036.
The asteroid, which is about 320 metres in diameter, ranks a 1 on the Torino scale. Zero means an object has no chance of hitting Earth and a 10 means certain impact. At one point, Apophis rated a 4.
Because the asteroid will travel too close to the Sun for radar measurements, this will probably be the last chance to get good radar data of Apophis for several years. But in 2013, the asteroid should be in a position where astronomers can track it with radar again.
"I think we'll be able to put this to rest one way or the other," Giorgini told New Scientist.
Giggle factor However, astronomers may be able to get optical data on Apophis before then, says Dave Tholen, an astronomer with the University of Hawaii, US.
In January, Tholen and his team plan to observe Apophis to determine its rotation rate. This is important because if the asteroid is heated unevenly by sunlight, the radiation can impart a small force on the asteroid. That force may be miniscule, but when it accumulates over 20 years, it can make the difference in whether Apophis passes through the keyhole or not, he says.
Even though the odds of this particular asteroid hitting Earth have been reduced dramatically, its early threat alerted the public to the potential of asteroid impacts. "Compared to 10 years ago, I'd say the giggle factor has been reduced considerably," Tholen says.
If he'd signed that damned Kyoto Accord then the asteroid's path would have been perfect, crashing into the oceans, setting off tsunamis and worldwide catastrophic disaster as nature intended. /sarc
ML/NJ
Nah, conservation of angular momentum keeps the earth from wobbling like crazy. :)
Think of gyroscopes.
I only clicked on this thread for a Stargate answer... ;-)
Spoon!!!
-PJ
Well, what would happen to the tides if the moon went wandering away?
OTOH, getting rid of the Moon might help with this crazy werewolf problem we've got down here. So there ARE pros and cons! ;-)
True, true. And those pesky Moonites, too.
All they do is use thier welfare checks to buy cheap Mexican beer. :)
Well maybe using calculus we can just chip off a small rock from its side that would just destroy the building at night when nobody is in it. Actually I don`t think we have to do anything, the Times seems to be doing quite well slowly destroying itself. If I had a dime for every person I met who has said they cancelled their subscription to the NY Times I could afford a Paris Hilton personal party appearance by now...(Read this article below)
Paris Hilton, Capitalist Tool
You think she’s dumb. Well, she’s dumb like a … mogul.
On Saturday night here in Cannes, Paris Hilton made $200,000 for an appearance at a charity function. A few weeks ago she pocketed $1 million in Vienna for a similar event, and she was flown first class to Austria, put up at the best hotel and treated like a princess.
What did she do for the money?
“All I had to do was wave, like this,” she says, imitating the royal palm turn.
Recently, I’m told, Paris’s father, Rick Hilton, dressed down a group of Paris’ agents at Endeavor, telling them they weren’t doing enough to market his daughter’s name and image.
“When people hear Paris Hilton, they don’t think of a hotel or some crummy city in Europe,” Hilton complained. “They think of my daughter.”
We’re really going to be thinking about her more in the weeks to come: on June 2, Paris’ first album will be released.
http://www.foxnews.com/story/0,2933,196395,00.html#2
Just curious...Will she be doing any more videos portraying her #1 claim to fame? BJ`s? It`s amazing to me that we have women over in Iraq putting their lives on the line day in day out and this waste of food and air gets more attention in the press for doing nothing more than spending daddys money and sucking c**k.
THERE'S CHEAP MEXICAN BEER!!!!!
Dammit. I wonder if I can get a refund on all that Top Ramen.
doing nothing more than spending daddys money and sucking c**k
So what you got against Boy George!!!!!
Stabilizing the EarthBut to tell you the truth, I really don't understand how the Moon somehow grabs the Earth's axis and holds it relatively steady at a tilt of 23 degrees. Or how without it, the Sun and Jupiter would grab it and yank us around like a dog with a bone. I mean, it's just this imaginary thing after all, right? You can't grab it. You can't push it. You can't pull it.The orientation of the Earth's rotation axis causes the annual seasonal variations of our climate, and small variations in its orientation contribute to the advance and retreat of the ice ages. The obliquity of the Earth, the angle that its spin axis makes with the perpendicular to its orbital plane, is now a modest 23.5 degrees, but this is sufficient to bring summer and winter as the northern or southern hemisphere is tilted toward or away from the Sun. Variation in the Earth's obliquity as small as ± 1.3 degrees, around a mean value of 23.3 degrees, may contribute to, or trigger, the ice ages.
Fig. 5.30. The climate forecast for a Moon-less Earth would be a lot bleaker. The gravitational pull of our large Moon acts as an anchor, limiting excursions in the Earth's rotation axis and keeping the climate relatively stable (Fig. 5.30). Without the Moon, the tilt of Earth's spin axis would vary chaotically between 0 and 85 degrees. Such large variations in the planet's obliquity would result in dramatic changes in climate. With an obliquity of 0 degrees, there would be no seasonal variation in the distribution of sunlight on Earth. At 85 degrees, the Earth's axis would be tipped completely over. The equatorial tropics could then be permanently in cold winter snows, and the poles would be alternately pointed almost directly at or away from the Sun over the course of a single year. Such wide climate changes might be hostile to many forms of life on Earth.
Ah, here it is. And will ping when I get home.
http://www.freerepublic.com/focus/f-news/1307719/posts?page=306#306
Hey, I could be wrong.
I wonder what mechanism would cause it just to "wobble" and stuff like the Tufts website says?
The earth's pretty hefty, after all. To move it around would require quite a bit of torque!
A third of the tides come from the Sun, that is, the tides would still be there, but they'd be one third their, uh, size or whatever.
Actually since nothing was done the risk is exactly the same as it was before.
It was hype and nothing more.
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